- It is a total genetic message encoded within the base sequence of the axons of the coding region of a gene.
- It is the collection of codons that specify amino acids.
- Every individual three-letter code word of genetic code is called a codon.
- It consists of three consecutive bases, composed of A, T, G, and C at different combinations.
- Each codon represents an amino acid.
- There are altogether 64 codons
1. Sense codon= 61
2. None sense codon: 3
- These are used to terminate protein synthesis.
- They are:- UAG, UAA, UGA
Characteristics of genetic code
- A codon representing a definite amino acid is universal and applicable to all organism
- The same codon specifies the same amino acid in all species.
2. Degeneracy/ Redundancy
- For a given amino acid there is more than one codon( except for methionine and tryptophan which have only one codon)
- Sense codon= 61
- Total amino acid= 20
So, for one amino acid, there is more than one codon
3. Specificity/ unambiguous
- Forgiven codon there is only one amino acid.
- Consecutive triplet codons do not share any base and follow the strict sequence along with the reading frame of mRNA.
5. Commaless/ Nonpunctuated
- Between the consecutive codons there are no extra bases to separate the codons.
Example:- abc def ghi